Signaling system.



H. L. DARRAH.

SIGNALING SYSTEM. APPLICATION FILED AUG. 12. 1913.

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Patented Dec. 14, 1915.

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HARRY L. DARRAH, OF CHA'IHAM, NEW JERSEY, ASSIGNOR 'IO WE STERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

SIGNALING SYSTEM.

Application filed August 12, 1913.

To all whom it may concern Be it known that I, HARRY L. DARRAH, a citizen of the United States, residing at Chatham, in the county of Morris and State of New Jersey, have invented a certain new and useful Improvement in Signaling Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to signaling systems, and more particularly to a circuit arin connection with such systems.

In telegraph, telephone and signaling systems it is often desirable to provide signaling means and to arrange such signaling means in the system so that it will respond only to currents of a certain character and will be unresponsive to currents of other kinds.

It is an object of this invention to obtain such result, and with this object in View a. circuit arrangement is employed by virtue of which the signaling device will respond only to a current impulse of substantial duration and will not respond to short impulses of current. Short impulses of current are absorbed, without operating the signal, by means of a series of relays operating in a predetermined sequence, the circuit arrangement'for these relays being such that, unless the impulse is of suflicient length to maintain the first relay of the series operated until the last relay of the series has also operated, the signal will not be displayed. Because of this arrangement false signals, due to line disturbances, lightning discharges and other short impulses of current encountered in telephone and telegraph systems, are eliminated.

For a. more complete understanding of the invention reference may be had to the accompanying drawing, wherein Figure 1 shows in diagram a circuit arrangement employed in a signaling system: and Fig. 2, also in diagram, at slightly different circuit arrangement employed in a similar system.

Referring first to the circuit arrangement shown in Fig. 1, 1 and 2 indicate the line conductors of an ordinary telephone, telegraph or signaling system. Obviously one of these conductors could be eliminated and a ground return substituted therefor with- Specification of Letters Patent.

Patented Dec. 14, 1915.

Serial No. 784,445.

out effecting the operation of the system hereinafter disclosed. Bridged across the line is an ordinary relay 3, having an armature 4 and a front contact 5. Controlled by the'relay 3 are three other relays, 6, 7 and 8, of which 6 and 8 are of the usual construction, and 7 is of the slow-acting or sluggish type, as indicated on the drawing. The relay 6 is provided with an armature 9 and front contact 10; the relay 7 with an armature 11, front contact 12 and back contact l3; and relay 8 with armatures 14 and 15, and contacts 16, 17 and 18, the contacts 16 and 17 being arranged relative to the armature 14 in such a way that the contact between the armature 1-1 and the contact 16 is made before contact between the contacts 16 and 17 is broken. The armature 11 of relay 7 and the contact 16 of relay 8 are connected to the ungrounded side of the battery l9, and armature 4 of the relay 3 is connected to ground at 20. On the drawing, the battery 19 is shown, for convenience, as several separate batteries, but in practice, as is well understood, these may all be replaced by a single battery located at the station with the signaling device. The signaling device, which may be of any well-known type, is indicated as a lamp 21, one side of which is connected to the contact 10 and the other to ground at .22. I

The operation of the system of Fig. 1 is as follows: Assume that a long impulse of signaling current is impressed on the line 1, 2. This will operate the relay 3 placing ground on the contact 5. The operation of the relay 3 will cause the operation of relays 6 and 7 over a circuit which may be traced as follows: battery 19, normally closed contacts 16 and 17, relay 7, relay 6, contact 5, armature 4, to ground at 20. The operation of the relay 7 causes the operation of the relay 8 over the following circuit: battery 19, armature 11, contact 12, relay 8. relay 6, contact 5, armature 1, to ground at 20. The operation of the relay 8 breaks the contact between 16 and 17 and opens the original energizing circuit for relays 6 and 7. As the relay 7 is of the sluggish or slowacting type, the relay 8 will operate before the relay 7 can fall back, so that the relay 6 is held up and the relay 8 is locked up over the following circuit: battery 19, contact 16, armature 14, relay 8, relay 6, contact 5, armature 4 to ground at 20. The releasing of the relay 7 closes a circuit for the lamp 21, provided the relays 8 and 6 remain locked up or in their operative position, which circuit may be traced as follows: battery 19, armature 11, back contact 13, armature 15, contact 18, armature 9, front contact 10, lamp 21 to ground at 22, thus lighting the lamp and giving a signal. It will be noted that this circuit for the lamp or signal is only closed in case the relay 7 is in its released position, and the relays 6 and 8 are in their operative position, and as these relays can be in such positions only in case the relay 3 has remained energized for a sufiicient length of time for the relay 6 to operate, the relays 7 and 8 to operate and the relay 7 to release, the signal 21 will be displayed only when a relatively long impulse of current is sent over the line. If a short impulse of current, such as that due to a lightning discharge, for instance, is impressed on the line, the relay 3 will operate, operating the relays 6 and 7, but before the relay 8 can operate and the relay 7 release, the relay 3 will fall back opening the signal or lamp circuit at 5 and de nergizing all of the relays 6, 7 and 8, and returning such relays to their normal positions.

In the circuit arrangement shown in Fig. 2, 1 and 2 represent the line conductors, and 23, 24, 25, 26 and 27 represent various relays. All of these relays are of the usual type,-except 24, which is a sluggish or slowrelease relay, and 25, which is provided with two windings. The relay 23 is provided with an armature 28 and a front contact 29, the armature 28 beingconnected to ground as indicated at 30. The relay 24, which is of the sluggish or slow-release type, as indicated on the drawing, is provided with an armature 31, a front contact 32, and a back contact 33, the armature 31 being connected to the ungrounded side of the battery 19.. The relay 25 is provided with two armatures, 34 and 35, a front contact piece 36, and a front contact 37. The contact piece 36 is connected to the ungrounded side of the battery 19, and cooperating with such contact piece is a contact 38, the arrangement being such that contact is made between the armature 34 and contact piece 36 before the contact between 36 and 38 is broken. The relay 26 is provided with an armature 39 and-a normally closed back contact 40, and the relay 27, which in this circuit may be considered either as the signal controlling device or signaling device itself, is provided with an armature 41 and front contact 42, the armature 41 being connected to ground at 43. Included in the circuit controlled by the signal relay 27 is a visual signal, which is shown as a lamp 44. The

such line, will operate and will remain op- 7 erated until the. signal impulse ceases. The

operation of relay 23 energizes the sluggish relay 21 over a circuit which may be traced as follows: from the ungrounded side of the battery 19, contacts 36 and 38, relay 21, contact 29, armature 28 to ground at 30. The operation of the relay 21 causes the operation of the relay 25 over the following circuit: battery 19, armature 31, contact 32, left-hand winding of relay 25, contact 29, and armature 28 to ground at 30. As this circuit includes the front contact of the relay 23, obviously the relay 25 will not be operated unless relay is still in its operative position. The operation of relay 25 breaks the contact between 36 and 38, and removes the battery from the relay 21 thus allowing said relay to fall back or release. As soon as relay 21 has released, the following looking circuit for relay 25 is established: battery '19, armature 31, contact 33, armature 39, contact 40, armature 35, contact 37, righthand winding of relay 25 to ground at 45. The signal relay 27 is also energized over a branch of'the same circuit as follows: battery 19, armature 31 contact 33, armature 39, contact 40, armature 35, contact 37, relay 27 to ground at 13. The operation of relay 27 closes at its front contact 42 a, circuit for the signal 11 and causes the display of such signal. It will be observed that the relay 27 can operate only when the relay 24 is released and the relay 25 is operated, and inasmuch as the relay 25 does not operate until after relay 21 has operated, it follows that in order to display the signal, the current impulse must be of sufiicient duration to maintain the relay 23 energized while the relay 21 operates, the relay 25 operates and the relay 21 releases. The signal 41 having been displayed, it may be erased by operating the key 16 which causes the operation of the relay 26, which in turn opens the energizing circuit of relays 25 and 27.

It is obvious that various arrangements of relays and circuits may be used without departing from the applicants invention, and that the time interval between the operation of the first or line relay and the signaling device may be adjusted by varying the number of relays in the series, and hence that the signaling device may be thus made responsive only to impulses which are sustained for an interval of time in excess of any given period.

I claim:

1. In a signaling system, an electroresponsive signaling device, an actuating circuit therefor normally open at a plurality of points, and a plurality of relays cotiperating to close said actuating circuit, one of said relays being energized and denergized to complete said circuit, whereby said signaling device is rendered unresponsive to short impulses of current.

2. In a signaling system, an electroresponsive device, an actuating circuit therefor open at a plurality of points, and a plurality of relays cooperating upon the energization of all, and a subsequent deenergization of one, to close said actuating circuit.

3. In a signaling system, an electroresponsive signaling device and an actuating circuit therefor normally open at a plurality of points, means for closing said circuit at one point upon the initiation of an impulse of current, means including a relay for maintaining said circuit open at another point until said relay has operated and released, whereby the signaling device Will not operate unless the impulse endures for a time greater than that necessary for the operation and release of said relay.

4. In a signaling system, an electroresponsi e signaling device and an actuating circuit therefor normally open at a plurality of points, means for closing said circuit at one point upon the initiation of an impulse of current, means including a slow responding relay for maintaining said circuit open at another point until said relay has operated and released, whereby the signaling device will not operate unless the impulse endures for a time greater than that necessary for the operation and release of said relay.

In Witness whereof, I hereunto subscribe my name this 9th day of August A. D.,

HARRY L. DARRAH. IVitnesses LAURA DORING, ALICE HAZLEY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. i 

